图书google香港SQL解析的书籍 http://books.google.com.hk/books?id=3i-NAgAAQBAJ&pg=PA71&lpg=PA71&dq=FromClauses+SchemaObjectTableSource&source=bl&ots=5Y9FckFDNw&sig=QpKPvOYmGkQVSUplXD9ZZKzDMz8&hl=zh-CN&sa=X&ei=VqQuU668OoKwiAfbt4CQDg#v=onepage&q=FromClauses%20SchemaObjectTableSource&f=false